System and method for energy rate balancing in hybrid automatic transmissions

ABSTRACT

A hybrid system includes a transmission control module, a power source, a transmission, and a drive train. The transmission control module partially operates the hybrid system and receives operating information from various components of the system, calculates power losses in the drive train, and calculates the driving torque needed to reach a target power profile determined from a driver&#39;s input.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 14/794,928filed Jul. 9, 2015, which is a continuation of International ApplicationNo. PCT/US2014/020499 filed Mar. 5, 2014, which claims the benefit ofU.S. Provisional Application No. 61/786,669 filed Mar. 15, 2013, whichare hereby incorporated by reference in their entirety.

BACKGROUND

The present disclosure generally relates to a hybrid vehicle drive trainand, more particularly, to a method of adjusting the torque output ofthe drive train to match a target power profile.

Over the past few years, there has been a growing concern over globalclimate change due to an increase in carbon dioxide levels as well asoil supply shortages. As a result, automobile manufactures and consumersare developing a greater interest in motor vehicles having loweremissions and increased fuel efficiency. One viable option is a hybridelectric vehicle which allows the vehicle to be driven by electricmotors, combustion engine, or a combination thereof.

Transmissions in hybrid drive trains serve a number of functions bytransmitting and manipulating torque in order to provide torque to anoutput member. The driver, through actuation of the accelerator, brakepedal, and auxiliary braking selectors, commands the engine and/orelectric motor to provide a desired power to the vehicle drive train.The transmission is expected to accurately implement the driver'scommand. As the transmission changes the gear ratio, the driver's intentis not always achieved. Gear shifts within transmissions often result indisturbances in the drive train power output profile. The disturbancesmanifest as vibrations in the vehicle which are felt by the driver andpassengers. Such disturbances can cause discomfort to the driver andpassengers or otherwise create an undesirable driving experience.

Hybrid vehicle drive trains provide additional options for tailoringpower output profiles based on a user's particular needs. For example,the power profile can be tailored to provide many different functionssuch as optimizing fuel economy, maximizing acceleration, reducing oreliminating vibrations from gear shifts, or otherwise smoothing thedrive train power profile for driver and passenger comfort. However,problems exist with transforming a drive train power input to a desireddrive train power.

Thus, there is a need for improvement in this field.

SUMMARY

The hybrid system described herein addresses several of the issuesmentioned above as well as others. In one example, a method foroperating a hybrid vehicle including a drive train having a transmissionand a power source includes the actions of receiving a command inputfrom a driver, determining a current state of the vehicle, determiningloss parameters of the drive train, establishing a target drive trainoutput power profile as a function of the command input, establishingpower loss within the drive train as a function of the loss parameters,establishing a requisite input power needed to reach the target drivetrain output power profile as a function of the loss parameters and thetarget drive train output power profile, and supplying the requisiteinput power to the drive train. The loss parameters can includehydraulic power loss, kinetic power loss, and clutch power loss.

The hydraulic power loss can be calculated as a function of hydraulicloss parameters within the transmission. The hydraulic loss parameterscan include the temperature of a hydraulic fluid, the pressure of thehydraulic fluid, and the flow rate of the hydraulic fluid.

The kinetic power loss can be calculated as a function of rotationalinertia loss parameters within the drive train. The rotational inertialoss parameters include the rotational inertia of at least one bodywithin the transmission, the rotational speed of the body, and therotational acceleration of the body. The kinetic power loss (P_(K)) iscalculated by the formula

$P_{k} = {\sum\limits_{1}^{N}\; {J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}}$

for i=1−N bodies, where J is the rotational inertia of the body, ω isthe rate of rotation of the body, and {dot over (ω)} is the rotationalacceleration of the body.

The clutch power loss is calculated as a function of clutch lossparameters within the transmission. The clutch loss parameters includetorque transmitted across the clutch during engagement between twoclutch plates, and the rotational speed of each clutch plate. The clutchpower loss (P_(clutch)) is calculated by the formula

$P_{clutch} = {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}$

for m=1−K bodies, where T_(clutch) is torque transmitted across theclutch during engagement between two clutch plates and |ω₁+ω₂| is theabsolute value of the difference between the rates of rotation of eachclutch plate.

The power source can include an engine in the hybrid module. Therequisite input power can be described as P_(engine)+P_(hybrid) and iscalculated by the formula

${P_{dl} = {P_{engine} + P_{hybrid} - P_{loss} - {\sum\limits_{1}^{N}\; {J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}} - {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}}},$

where P_(d1) is the target drive train output power profile, J is therotational inertia of i=1−N bodies in the transmission, ω is the rate ofrotation of i=1−N bodies in the transmission, {dot over (ω)} this therotational acceleration of i=1−N bodies in the transmission, T_(clutch)is the torque transmitted across m=1−K clutches during engagementbetween two clutch plates, and |ω₁−ω₂| is the magnitude of thedifference between the rates of rotation of two clutch plates in m=1−Kclutches. The calculations can be performed by a transmission/hybridcontrol module.

In one example, a method for operating a hybrid vehicle having a drivetrain including a transmission and a power source includes the actionsof establishing a target drive train output power profile, establishinghydraulic power loss of the drive train as a function of hydraulic lossparameters within the transmission, establishing kinetic power loss ofthe drive train as a function of rotational inertia loss parameterswithin the drive train, establishing clutch power loss of the drivetrain as a function of clutch loss parameters within the transmission,establishing the drive train input power needed to reach the drive trainoutput power profile as a function of the hydraulic loss parameters, therotational inertia loss parameters, and the clutch loss parameters, andadjusting torque supplied by the power source to reach the target drivetrain output power profile.

The hydraulic loss parameters can include the temperature of a hydraulicfluid, the pressure of the hydraulic fluid, and the flow rate of thehydraulic fluid. The rotational inertia loss parameters can include therotational inertia of a body within the transmission, the rotationalspeed of the body, and the rotational acceleration of the body. Thekinetic power loss (P_(K)) can be calculated by the formula

${P_{K} = {\sum\limits_{1}^{N}{J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}}}\;$

for i=1−N bodies, where J is the rotational inertia of the body, ω isthe rate of rotation of the body, and {dot over (ω)} is the rotationalacceleration of the body.

The clutch loss parameters can include torque transmitted across theclutch during engagement between two clutch plates, and the rotationalspeed of each clutch plate. The clutch power loss (P_(clutch)) can becalculated by the formula

$P_{clutch} = {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}$

for m=1−K bodies, where T_(clutch) is the torque transmitted across theclutch during engagement between two clutch plates and |ω₁−ω₂| is theabsolute value of the difference between the rates of rotation of eachclutch plate.

The power source can include an engine and the hybrid module. The torquesupplied by the power source can be characterized asP_(engine)+P_(hybrid) and is calculated by the formula

${P_{dl} = {P_{engine} + P_{hybrid} - P_{loss} - {\sum\limits_{1}^{N}\; {J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}} - {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}}},$

where P_(dl) is the target drive train output power profile, J is therotational inertia of i=1−N bodies in the transmission, ω is the rate ofrotation of i=1−N bodies in the transmission, {dot over (ω)} is therotational acceleration of i=1−N bodies in the transmission, T_(clutch)is torque transmitted across m=1−K clutches during engagement betweentwo clutch plates, and |ω₁−ω₂| is the magnitude of the differencebetween the rates of rotation of two clutch plates in m=1−K clutches.

The disclosure further includes an apparatus for performing any of theactions described herein. Further forms, objects, features, aspects,benefits, advantages, and embodiments of the present disclosure willbecome apparent from a detailed description and drawings providedherewith.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a diagrammatic view of one example of a hybridsystem.

FIG. 2 illustrates a general diagram of an electrical communicationsystem in the FIG. 1 hybrid system.

FIG. 3 illustrates a power output profile of a hybrid system withoutenergy balancing.

FIG. 4 illustrates a power output profile of a hybrid system with energybalancing.

FIG. 5 illustrates a power output profile of a hybrid system withincreased energy balancing.

FIG. 6 illustrates a flow chart showing of actions of a method tobalance energy within a hybrid vehicle.

DESCRIPTION OF THE SELECTED EMBODIMENTS

For the purpose of promoting an understanding of the principles of thedisclosure, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of thedisclosure is thereby intended. Any alterations and furthermodifications in the described embodiments, and any further applicationsof the principles of the disclosure as described herein are contemplatedas would normally occur to one skilled in the art to which thedisclosure relates. One embodiment of the disclosure is shown in greatdetail, although it will be apparent to those skilled in the relevantart that some features that are not relevant to the present disclosuremay not be shown for the sake of clarity.

The reference numerals in the following description have been organizedto aid the reader in quickly identifying the drawings where variouscomponents are first shown. In particular, the drawing in which anelement first appears is typically indicated by the left-most digit(s)in the corresponding reference number. For example, an elementidentified by a “100” series reference numeral will first appear in FIG.1, an element identified by a “200” series reference numeral will firstappear in FIG. 2, and so on. With reference to the Specification,Abstract, and Claims sections herein, it should be noted that thesingular forms “a”, “an”, “the”, and the like include plural referentsunless expressly discussed otherwise. As an illustration, references to“a device” or “the device” include one or more of such devices andequivalents thereof.

FIG. 1 shows a diagrammatic view of a hybrid system 100 according to oneembodiment. The hybrid system 100 illustrated in FIG. 1 is adapted foruse in commercial-grade trucks as well as other types of vehicles ortransportation systems, but it is envisioned that various aspects of thehybrid system 100 can be incorporated into other environments. As shown,the hybrid system 100 includes a drive train 108 having a transmission106, power sources in the form of an engine 102 and hybrid module 104,and a drive shaft 107. The drive train 108 is positioned to transferpower between the power sources and wheels 110. The hybrid module 104incorporates an electrical machine, commonly referred to as an eMachine112, and a clutch that operatively connects and disconnects the engine102 from the eMachine 112 and the transmission 106. An energy storagesystem 134 is operatively coupled to an inverter 132 and the eMachine112.

The transmission 106 is an automatic transmission that is capable ofautomatically changing gear ratios as the vehicle moves. Thetransmission 106 has variable gear ratios which can be selected orchanged in an automatic fashion during operation. The transmission 106can be a variety of types, but commonly is a hydraulic transmissionincluding one or more planetary gearsets and a plurality of clutches.The planetary gearset(s) is a compound epicyclic gearset having one ormore outer gears revolving about a central gear. The gearset(s)typically includes bands and clutches actuated by hydraulic servos. Ahydraulic fluid (such as a lubricating or automatic transmission fluid)provides lubrication, corrosion prevention, and a hydraulic medium toconvey mechanical power for operation of the transmission. In someembodiments, the transmission 106 includes a torque converter forhydraulically connecting the power sources to the transmission 106. Thetransmission 106 can include a pump which draws the hydraulic fluid froma sump and circulates the fluid throughout the transmission 106 and/orpressurizes it for input to a torque converter housing. Transmission 106can include a fluid cooling system for maintaining the temperature ofthe hydraulic fluid. The cooling system can be shared with othercomponents of the hybrid system 100 or it can be a dedicated to thetransmission 106. In some embodiments, the transmission 106 is fluidlyconnected with the hybrid module 104. The transmission 106 includes aninput shaft which is coupled to the hybrid module 104 and an outputshaft which is coupled to the drive shaft 107.

The hybrid system 100 incorporates a number of control systems forcontrolling the operations of the various components. For example, theengine 102 has an engine control module 146 that controls variousoperational characteristics of the engine 102 such as fuel injection andthe like. A transmission/hybrid control module 148 substitutes for atraditional transmission control module and is designed to control boththe operation of the transmission 106 as well as the hybrid module 104.The transmission/hybrid control module 148 and the engine control module146 along with the inverter 132, energy storage system 134, and a DC-DCconverter system 140 communicate along a communication link as isdepicted in FIG. 1. In a typical embodiment, the transmission/hybridcontrol module 148 and engine control module 146 each comprise acomputer having a processor, memory, and input/output connections.Additionally, other vehicle subsystems may also contain computers havingsimilar processors, memory, and input/output connections. Duringoperation, the transmission/hybrid control module 148 receivesinformation from various components of the vehicle, determines theappropriate gear ratio and implements changes, or shifts between gearratios upon acceleration or braking demands from the driver. The systemincludes a shift selector 152 for selecting whether the vehicle is indrive, neutral, reverse, etc.

FIG. 2 shows a diagram of one example of a communication system 200 thatcan be used in the hybrid system 100. While one example is shown, itshould be recognized that the communication system 200 in otherembodiments can be configured differently than what is shown. Thehybrid/transmission control module 148 includes a hybrid data link and avehicle data link through which most of the various components of thehybrid system 100 communicate. In particular, the data links facilitatecommunication between the transmission/hybrid control module 148, theengine control module 146, the energy storage system 134, the inverter132, the shift selector 152, and the DC-DC converter system 140 as wellas other components.

Various information is exchanged or communicated between thetransmission/hybrid control module 148 and other various components. Interms of general functionality, the transmission/hybrid control module148 receives power limits, capacity available current, voltage,temperature, state of charge, status, and fan speed information from theenergy storage system 134 and the various energy storage modules within.The transmission/hybrid control module 148 in turn sends commands forconnecting the various energy storage modules so as to supply voltage toand from the inverter 132. From the inverter 132, thetransmission/hybrid control module 148 receives a number of inputs suchas the motor/generator torque that is available, the torque limits, theinverter's voltage current and actual torque speed. Based on thatinformation, the transmission/hybrid control module 148 controls thetorque speed. From the inverter 132, the transmission/hybrid controlmodule 148 also receives a high voltage bus power and consumptioninformation. The transmission/hybrid control module 148 alsocommunicates with and receives information from the engine controlmodule 146 and in response controls the torque and speed of the engine102 via the engine control module 146.

The various components of the hybrid system 100 as well as theirfunction are discussed in further detail in U.S. patent application Ser.No. 13/527,953, filed Jun. 20, 2012 and International Application No.PCT/US2011/041018, filed Sep. 9, 2011, published as WO 2012/034031 A2,which are hereby incorporated by reference.

Disclosed herein is a method of controlling the drive train powerprofile. As used herein “power profile” refers to the torque profiledelivered to wheels 110 over a given period of time. A target drivetrain output power profile (target power profile) is tailored to producea specific power profile in response to a command from the driver.Driver commands can include actuating the accelerator, releasing theaccelerator, actuating the brake pedal, releasing the brake pedal,engaging auxiliary braking selectors, or any combination, degree, orvariance of the same. The method generally includes setting a targetpower profile in response to a driver command, determining thecumulative power losses of the drive train, and adjusting the powerinput from the power sources so that the actual power delivered towheels 110 (i.e. actual power profile) matches the target power profile.The target power profile is monitored continuously or during setintervals over time and adjusted based on new or different drivercommands. Various operating parameters of the drive train 108 arelikewise monitored continuously or during set intervals in order tocalculate the power losses and actual power delivered to wheels 110 atany given moment. Power losses are generally defined as energy lossesover a period of time. Power losses are commonly dependent on a severalloss parameters at any given moment and change with variance in the lossparameters. Power losses do not necessarily occur linearly, and variousrelationships between energy loss and time are described below.

During operation, various operating parameters of the drive train 108are known, monitored, and/or calculated by the transmission/hybridcontrol module 148 and used when determining the amount of torque thatis necessary to achieve the target power profile. Operating parametersare divided herein into the vehicle data and loss parameters. Lossparameters include hydraulic power loss, kinetic power loss, and clutchpower loss. Vehicle data includes in part the rotational speed of theengine 102 output shaft, the rotational speed of the hybrid module 104,and the speed and acceleration of the vehicle (including the rotationalspeed of the drive shaft 107. Examples of loss parameters include thegear configuration of the transmission 106, the rotational speeds ofeach part of the transmission 106 (i.e. various groupings of gears), thetemperature and pressure of the hydraulic fluid in the transmission, andthe state of engagement of all of the clutches in transmission 106. Thesampled values are transmitted to or obtained by the transmission/hybridcontrol module 148.

More specifically, several losses occur in the transmission 106hydraulic system. Certain parameters of the transmission 106 hydraulicsystem are known (i.e. hydraulic loss parameters). A sensor positionedalong the fluid flow path of the hydraulic fluid monitors and reportsthe temperature of the hydraulic fluid. Similarly, a sensor monitors andreports the pressure of the hydraulic fluid. The flow rate of thehydraulic fluid is also monitored and reported. Energy losses occur dueto fluid friction from moving parts and moving fluid as well as lossesfrom oil pressure changes. Efficiency of the hydraulic system varieswith variances in the temperature of the fluid. Energy dissipated (andtherefore lost) within the transmission 106 due to the transmissionhydraulic system have been determined through testing and are generallywell known for any given values of these loss parameters. Such lossesfor any given values of these loss parameters are denoted herein asequation (1):

P _(loss)=transmission hydraulic system losses  (1)

Other loss parameters include the rotational rates and acceleration ofall rotating parts in the drive train 108. Generally, energy lossesoccur when rotating parts maintain, change, or reverse rotationalspeeds. The kinetic energy of a rotating body is describedmathematically as E=½Jω², where J is the rotational inertia of the body,and co is the angular velocity of the body. The rotational inertia (orpolar moment of inertia) is the property of the body that measures itsresistance to rotational acceleration about an axis, i.e. the degree ofoutside force necessary to reduce the rotation rate of the body. Therotational inertia of various parts of the transmission 106 for everypossible gear and clutch configuration has been determined throughtesting and are well known. Generally, for each configuration one ormore groups of components rotate in unison (not including transitoryperiods of clutch engagement and disengagement), and the rotationalinertia of each group is determined. Power is defined as the time rateof change of energy, so the power of a rotating body can be found bytaking the time derivative of E. Therefore the power is

${P = {\frac{E}{t} = {J\; \omega \overset{.}{\omega}}}},$

where {dot over (ω)} is the time derivative of ω

$\left( {i.e.\frac{\omega}{t}} \right),$

or the rotational acceleration of the body. Practically, the rotationalacceleration can be determined from or quantified as the surplus ofpower versus the load, or in the case of the drive train, the rotationalacceleration is dependent on the power available and the weight of thevehicle and can be determined accordingly. The rotational speed ofbodies in the drive train are known through sensors and/or knownrelationships between input values and various gear configurations.Thus, the total power loss due to kinetic energy dissipation (kineticpower loss) can be expressed and calculated according to equation (2):

$\begin{matrix}{P_{k} = {\sum\limits_{1}^{N}\; {J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}}} & (2)\end{matrix}$

for N groups of components rotating in unison (i.e. i=1−N), where J, ω,and {dot over (ω)} are known values for any given set of lossparameters.

Other loss parameters are related to engagement of the clutches in thetransmission 106. A clutch is a mechanical device for controlling theconnection between two rotating bodies. Clutches generally include twometal plates that are pressed together by hydraulic force. When pressedtogether, frictional forces couple the two plates and connect the bodiesso that they rotate in unison. During the coupling, energy is dissipatedin the form of heat due to the friction between the two plates.Solenoids are included in the transmission 106. A solenoid includes ahelically-wound coil which creates a magnetic field upon excitation ofthe coil. Such magnetic fields are harnessed and used to apply a linearhydraulic force to one or both plates in a clutch. The torquetransmitted across the clutch during engagement is denoted byT_(clutch). The slip across the clutch is denoted as |ω₁−ω₂|, whereω₁−ω₂ is the difference between the rates of rotation of the two clutchplates. The power dissipated during engagement of a clutch (i.e.transmission clutch power loss, or clutch losses) is then describedaccording to equation (3):

$\begin{matrix}{P_{clutch} = {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}} & (3)\end{matrix}$

for K clutches (i.e. m=1−K). Through testing, the torque transmittedacross various clutches in transmission 106 has been determined as afunction of the current applied to the coil(s). Therefore, the powerloss in each clutch is known as a function of the current applied to thecoil and the angular rotation rates of the two plates. Clutch lossesoccur when changing gears, as clutches either engage or disengage. Whengears are not changing during operations, the clutch losses are zero andneed not be calculated.

When all the power losses are known, the power needed from the powersources to maintain or achieve the target power profile are calculatedaccording to equation (4):

P _(dl) =P _(engine) +P _(hybrid) −P _(loss) −P _(K) −P _(clutch)  (4)

or, alternatively as equation (5):

$\begin{matrix}{P_{dl} = {P_{engine} + P_{hybrid} - P_{loss} - {\sum\limits_{1}^{N}\; {J_{i_{1 - N}}\omega_{i_{1 - N}}{\overset{.}{\omega}}_{i_{1 - N}}}} - {\sum\limits_{1}^{K}\; {T_{{clutch}_{m_{1 - K}}}{{\omega_{1} - \omega_{2}}}_{m_{1 - K}}}}}} & (5)\end{matrix}$

where P_(dl) is the target power profile, P_(engine) is the engine 102power, and P_(hybrid) is the hybrid module 104 power.

FIGS. 3, 4, and 5 illustrate example implementations of different powerprofiles. FIG. 3 illustrates an example power profile according tocurrent methods in which no target power profile is applied. Thehorizontal axis represents time and the vertical axis represents power.A user command profile 302 represents the users application of theaccelerator. The profile of the user command profile 302 shows aninitial steep slope beginning at zero which tapers off into a linehaving zero slope. The user command profile 302 can be characterized asa command for smooth acceleration until a desired vehicle speed isachieved. At 304, the desired speed is achieved and the user releasesthe accelerator and correspondingly the user command profile 302 returnsto zero, indicating a desire to maintain or reduce the speed of thevehicle. Although the user command profile 302 indicates a desire forsmooth acceleration, the vehicle does not deliver the desired powerprofile. Rather, the exemplary power profile 306 is achieved. Theregions 308 and 310 indicate areas where gear changes occur. The region308 indicates an upshift, and the region 310 indicates a downshift. Ineach of the regions 308 and 310, the power profile exhibits adisturbance. Generally, gear changes in automatic transmissions causevariances in torque applied to the wheels of the vehicle. This is due inpart to a continuous supply of power from the power source even whilethe gear is disengaged. As a clutch disengages, the continuous supply ofpower causes an upsurge 312 in the power profile. Subsequently there-engagement of the gears in the higher gear causes a downsurge 314 inthe power profile. The continuous supply of power from the power sourcethen causes the power profile to continue an upward trend in the newgear. A similar result happens during a downshift as shown in the region310. The upsurge and downsurge in the regions 308 and 310 createdisturbances in the drive train 108 which manifest as vibrations orother unwanted characteristics to the driver.

The details disclosed herein provide a method to precisely control thepower profile of the vehicle and to create a driving experience that ismore comfortable and/or custom tailored to the user's wishes. FIG. 4illustrates a further example of a power profile. The user commandprofile 302 again illustrates a command for smooth acceleration to adesired vehicle speed. A target power profile 402 diverges from theexemplary power profile 306 in the regions 408 and 410. The target powerprofile is chosen to minimize the disturbance in the drive train 108during gear shifts by reducing the magnitude of the profile disturbancesin regions 408 and 410.

FIG. 5 illustrates a further example showing a target power profile 502.The figure again illustrates the user command profile 302 which callsfor a smooth acceleration to a desired vehicle speed at 504. Theexemplary power profile 306 is shown again for comparison. The targetpower profile 502 continues without significant disturbance throughoutthe gear shifts in the regions 508 and 510. Such a power profile createsa significantly smoother acceleration experience than that provided bythe exemplary power profile 306.

Realization of the target power profile 502 is achieved according to themethods described herein, including obtaining the loss parameters,calculating the power losses in the drive train 108, and determining thelevel of torque that is needed at the transmission input shaft in orderto maintain the target power profile 502 at the wheels 110 of thevehicle. Values for each of the loss parameters described herein aresampled regularly for each operating state (i.e. gear positions, speedof motors, speed of wheels, etc) and received by the transmission/hybridcontrol module 148. When the engine 102 and/or the hybrid module 104 arealready rotating and/or supplying torque to the drive train 108, thatspeed or torque information is conveyed to the transmission/hybridcontrol module 148 along with the speed of wheels 110. In some cases thevalues of the loss parameters are sampled at specific intervals (e.g.50-100 samples per second). Each sampling produces a result set ofvalues.

An algorithm describing the method disclosed herein will now bedescribed according to FIG. 6. In a typical operation, the vehicle maybe at any number of operational states (stopped, constant velocity,accelerating, decelerating, etc.). The driver executes a driver input(or command input) which could be actuation of the accelerator, brake,or auxiliary brake command. The transmission/hybrid control module 148receives the driver input at action 600.

Current vehicle operational data is transferred to thetransmission/hybrid control module 148 at action 602. This includesinformation related to the current operation of the engine 102, thehybrid module 104, energy storage system 134, and the vehicle. Theengine 102 speed, power (or torque produced), and limits associated withspeed and power are obtained from the engine control module 146 over thevehicle data link. Data is also obtained regarding the speed, power (ortorque produced), for all hybrid motors (i.e. hybrid module 104).Information related to the hybrid power capabilities is obtained fromthe energy storage system 134 over the hybrid data link. Data related tothe vehicle such as wheel 110 speed and/or acceleration is alsoobtained. The transmission/hybrid control module 148 stores thesevalues. In some embodiments, the transmission/hybrid control module 148measures operational data directly. In other embodiments, any datadescribed herein is measured and/or obtained by any of a variety ofsensors and controllers, with the data ultimately being obtained by asingle controller for processing.

At action 604, the transmission/hybrid control module 148 obtains theloss parameters necessary to calculate the losses according to equations(1), (2), and (3). The loss parameters (as already described above)include the gear configuration of the transmission 106, the currentconfiguration of gears in the transmission including rotational speeds(ω), acceleration ({dot over (ω)}), and rotational inertia (J) of each.If a gear change is in progress, then loss parameters for each clutchundergoing change are obtained, such as angular rotation speeds (ω₁ andω₂) of each clutch plate and the value of the torque across the clutch(T_(clutch)). The temperature of the hydraulic fluid in the transmission106 as well as the pressure and flow rate of the hydraulic fluid areobtained. The three values of the pressure losses are then calculated(equations (1), (2), and (3)) and stored by the transmission/hybridcontrol module 148.

At action 606, the transmission/hybrid control module 148 calculates atarget power profile (P_(dl)) based on the driver input received inaction 600. The target power profile (P_(dl)) is determined based on auser's specific preference and can be tailored in a variety of ways. Forexample, the target power profile can be chosen to optimize fueleconomy, maximize acceleration, cancel power fluctuations fromtransmission shifts, or smooth the drive line power profile for drivercomfort. For example, the smooth slope of the target power profile 502of FIG. 5 is optimized to cancel power fluctuations from transmissionshifts and/or to increase fuel efficiency. A target power profileoptimized for increased acceleration would have a steeper initial slopethat tapered off earlier than the point 504. Some of these objectivesmay exclude others. For example, a profile chosen to optimize fueleconomy is generally incompatible with a profile chosen to maximizeacceleration. The strategy behind the profile selection may change atvarious times during the service life of the vehicle. In some cases, theprofile can be user-selectable. For example, in some embodiments, aninterface is placed within the cab or elsewhere on the vehicle so thatthe user can choose a target power profile based on an immediate orchanged need during operation. In other embodiments, the target powerprofile is not selectable by the user (e.g. in situations where an ownerprefers to maximize fuel economy in contrast to the driver who prefersto maximize driver comfort or acceleration).

At action 608, the transmission/hybrid control module 148 calculates thepower requirement from the engine 102 and the hybrid module 104(P_(engine)+P_(hybrid)) that is needed to meet the target power profileaccording to equation (4), which includes consideration of thedifference between the actual power profile and the target powerprofile. In other words, equation (4) is solved forP_(engine)+P_(hybrid). The transmission/hybrid control module 148 sendstorque commands to the engine control module 146 and the hybrid module104, and the engine 102 and hybrid module 104 are set to best achieveP_(engine)+P_(hybrid). The torque commands are executed, and the targetpower profile is achieved.

Operation of the engine 102 and hybrid module 104 are tailored to makethe actual power profile match the target power profile, as describedbelow. Because the sampling and calculations are performed many timesper second, any commands sent to the power sources which are needed tomaintain the target power profile are immediately conveyed. Similarly,because the sampling occurs frequently, any changes to the state of thevehicle or driver inputs (e.g. change from acceleration to brake orchange in incline of a road) are immediately considered. In this way,the target power profile can change and still be maintained by thevehicle.

Generally, a determination is made as to the appropriate split in powerbetween the two power sources in order to make the actual power profilematch the target power profile with the user's goal in mind, as eachpower source has different efficiencies and/or operating limits at anygiven operating condition. For example, the state of charge of theenergy storage system 134 informs the transmission/hybrid control module148 as to how much of the power can be provided by hybrid module 104 atany given moment and at what efficiency.

As mentioned previously, the drive train 108 couples the power sources(i.e. the engine 102 and the hybrid module 104) to the wheels 110.Torque can be transferred to an input shaft of transmission 106independently by either the engine 102 or the hybrid module 104.Alternatively, the engine 102 and the hybrid module 104 can work inconjunction to transfer torque to the transmission 106. The hybridmodule clutch allows the hybrid module 104 to couple or decouple withthe engine 102 so that the hybrid module 104 can be turned by the engine102, independently supply torque to the input shaft of the transmission106, or work in conjunction with the engine 102 to supply torque to theinput shaft of the transmission 106. Each power source has particularefficiency advantages and missions for a variety of different operatingconditions. An algorithm executed by the transmission/hybrid controlmodule is used to maintain a balance of the power sources that mostefficiently realizes both the target power profile and other operatingconsiderations.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges, equivalents, and modifications that come within the spirit ofthe disclosures defined by following claims are desired to be protected.All publications, patents, and patent applications cited in thisspecification are herein incorporated by reference as if each individualpublication, patent, or patent application were specifically andindividually indicated to be incorporated by reference and set forth inits entirety herein.

1-37. (canceled)
 38. A method, comprising: controlling a power sourceoutput power of a vehicle using a controller, wherein the vehicle has adrive train and a power source, and wherein the controller controls thepower source and the drive train; determining a target drive trainoutput power using the controller, wherein the target drive train outputpower is determined using a command input; determining the power sourceoutput power using the controller, wherein the target drive train outputpower is derived from the power source output power; and wherein thecontroller determines the power source output power using one or moreloss parameters and the target drive train output power; wherein theloss parameters include a hydraulic power loss, and wherein thehydraulic power loss is calculated as a function of hydraulic lossparameters calculated using measured properties of hydraulic fluid inthe drive train.
 39. The method of claim 38, further comprising:calculating a power loss within the drive train using the controller,the controller calculating the power loss using the one or more lossparameters, and controlling the power source output power provided tothe drive train using the controller.
 40. The method of claim 38,wherein the hydraulic loss parameters include a temperature of ahydraulic fluid in the drive train.
 41. The method of claim 38, whereinthe hydraulic loss parameters include a pressure of the hydraulic fluidin the drive train.
 42. The method of any one of claim 38, wherein thehydraulic loss parameters include a flow rate of a hydraulic fluid inthe drive train.
 43. The method claim 38, wherein the power sourceincludes an engine and a hybrid module, wherein the hybrid moduleincludes an electric motor.
 44. The method of claim 38, wherein thedrive train includes a sensor positioned along a fluid flow path of thehydraulic fluid that is configured to report the temperature of thehydraulic fluid.
 45. The method of claim 38, wherein the drive trainincludes a sensor positioned along a fluid flow path of the hydraulicfluid that is configured to report the pressure of the hydraulic fluid.46. The method of claim 38, wherein the drive train includes a sensorpositioned along a fluid flow path of the hydraulic fluid that isconfigured to report the flow rate of the hydraulic fluid.
 47. A method,comprising: determining a target drive train output power profile usinga control module, wherein the target drive train output power profile isdetermined using a command input; determining an input power using thecontrol module, wherein the input power is sufficient to supply thetarget drive train output power profile; and controlling a hybridvehicle according to the output power profile using a control module,wherein the hybrid vehicle has a power source and a drive train, andwherein the control module controls the drive train and the powersource; wherein the control module establishes the input power using oneor more loss parameters and the target drive train output power profile;wherein the loss parameters include a hydraulic power loss, and whereinthe hydraulic power loss is calculated as a function of hydraulic lossparameters; and wherein the hydraulic loss parameters include atemperature of a hydraulic fluid in the drive train.
 48. The method ofclaim 47, further comprising: determining a current state of the vehicleusing the control module; calculating a power loss within the drivetrain using the control module, the control module calculating the powerloss using the one or more loss parameters; and controlling the powersource to provide the input power to the drive train using the controlmodule.
 49. The method of claim 47, wherein the hydraulic lossparameters include a pressure of the hydraulic fluid in the drive train.50. The method of claim 47, wherein the hydraulic loss parametersinclude a temperature of a hydraulic fluid in the drive train.
 51. Themethod of any one of claim 47, wherein the hydraulic loss parametersinclude a flow rate of a hydraulic fluid in the drive train.
 52. Themethod claim 47, wherein the power source includes an engine and ahybrid module, the hybrid module having an electric motor.
 53. Themethod of claim 47, wherein the target drive train output power profileis represented by the following equation:P _(dl) =P _(engine) +P _(hybrid) −P _(loss) −P _(K) −P _(clutch) where:P_(dl)=A target drive train output power profile; P_(engine)=Enginepower; P_(hybrid)=Hybrid module power; P_(loss)=A hydraulic power loss;P_(K)=A kinetic power loss; P_(clutch)=A clutch power loss.
 54. Themethod of any one of claim 47, wherein the act of calculating a powerloss is performed before the control module controls the power source toprovide the input power to the drive train.
 55. The method of any one ofclaim 47, wherein the act of calculating a power loss is performed atsubstantially the same time the control module controls the power sourceto provide the input power to the drive train.
 56. The method of claim47, wherein the drive train includes a sensor positioned along a fluidflow path of the hydraulic fluid that is configured to report thetemperature of the hydraulic fluid.
 57. The method of claim 47, whereinthe drive train includes a sensor positioned along a fluid flow path ofthe hydraulic fluid that is configured to report the pressure of thehydraulic fluid.
 58. The method of claim 47, wherein the drive trainincludes a sensor positioned along a fluid flow path of the hydraulicfluid that is configured to report the flow rate of the hydraulic fluid.